A lot of people are saying that if they wanted her dead they could have killed her already, but if it's for the ceremony chances are they wouldn't have just killed her by any means necessary. Lucy was mentoring her on steps and enochian for a reason, they were giving her shots for a reason, obviously if death was involved there would be more to it than just gunning her down. Just because the ceremony is for the Order doesn't mean that death or injury HAS to be involved, but that also doesn't rule out the possibility that it is.
If they want her to come willingly, they wouldn't harm her before that time presented itself.
Especially if they have a precise way of carrying out the ceremony. Killing her beforehand would serve no purpose if there was order to the Order's (badum bum... oh that was bad ) way of doing the ceremony.
I mean think about it, for such a secretive religion, they have to have some sort of guidelines or laws about the way they execute things like this. Especially if it is something of great importance.
"Some things are secret for a reason. There are people whose lives are dedicated to keeping them that way."
That has to have some reflection on how they conduct themselves.